Growth of egg freezing blurs 'experimental' label

The first thing that Alison Hopkins did after finishing her PhD was freeze 14 of her eggs. She knew she wanted children, but she was 38 and didn't have a partner. "It buys you time, it eliminates any pressure," she says. "I thought it was a really good insurance policy."

For such women, however, egg freezing is "a shot in the dark", says Hopkins' fertility specialist, John Jain, who heads Santa Monica Fertility in California. Very few of the older women who have frozen eggs to beat the clock have tried to use them, says Jain. He estimates that, worldwide, fewer than ten babies have been born from eggs frozen for women aged 38 or over. And no one knows how successful the freezing and thawing of older eggs will be — despite the fact that most women now seeking the service are over 38.

These uncertainties are reflected in the recommendations of the American Society for Reproductive Medicine (ASRM) — the advisory body to the fertility industry — but not in the practices of its members, even some of...